后注浆对旋挖钻孔灌注桩受力性能影响研究

发布时间：2018-09-16 21:14

【摘要】：旋挖钻孔灌注桩由于受到施工工艺的影响,往往会在桩端和桩侧残留有沉渣和泥皮,这将严重影响灌注桩的承载性能。为此,通过对桩端和桩侧进行高压注浆的方式,改善桩底沉渣和桩侧泥皮带来的负面影响,可以大幅度提高灌注桩的承载能力,降低桩顶沉降。目前,关于后注浆对提高旋挖钻孔灌注桩承载性能的理论研究并不完善,对于该项技术也没有一项统一的规范标准。本文主要是通过室内模型试验对注浆桩进行一系列的研究,主要包括对未注浆桩、桩侧注浆桩和桩端注浆桩的极限承载力、桩身轴力和桩侧摩阻力进行测试并相互对比。分析三种情况下桩身受力情况与机理,并对比FLAC3D数值模拟结果与试验结果,验证FLAC3D软件对注浆桩相关问题进行数值模拟的可行性。除此之外,本文运用FLAC3D软件分析了秦皇岛汤河国际住宅项目2号楼工程桩基础的极限承载能力。以此工程实例为背景,模拟分析了桩侧不同的注浆位置、间距和半径,同时对比桩端注浆、桩侧注浆和桩端桩侧联合注浆对灌注桩受力性能的影响。最终,总结得到了一系列规律,希望通过这些规律来指导实践,可以对实际工程有所帮助。研究表明,后注浆能有效地改善桩土接触面与桩周土体的物理性能,挤压桩周土体,提高单桩承载能力。注浆位置越低,注浆半径越大,桩身承载力越能得到有效地提高。注浆间距的改变对注浆桩受力性能的影响并不明显。桩端桩侧联合注浆对提高桩身承载力的效果要好于桩端注浆桩和桩侧注浆桩,桩端注浆效果优于桩侧注浆效果。
[Abstract]:Because of the influence of the construction technology, there are always sediment and mud skin in the pile end and side, which will seriously affect the bearing capacity of the pile. Therefore, by means of high pressure grouting at the end and side of the pile, the negative effects of sediment on the bottom of the pile and mud on the side of the pile can be improved, the bearing capacity of the cast-in-place pile can be greatly increased and the settlement of the top of the pile can be reduced. At present, the theoretical research on post-grouting to improve the bearing capacity of rotary excavated cast-in-place pile is not perfect, and there is no uniform standard for this technology. In this paper, a series of research on grouting pile is carried out through laboratory model test, including the ultimate bearing capacity of non-grouting pile, pile side grouting pile and pile end grouting pile, the axial force of pile and the friction of pile side, and compared with each other. This paper analyzes the stress and mechanism of pile body under three kinds of conditions, and compares the results of FLAC3D numerical simulation with experimental results, and verifies the feasibility of numerical simulation of grouting pile related problems by FLAC3D software. In addition, this paper analyzes the ultimate bearing capacity of pile foundation of No. 2 building of Tanghe International Residential Project in Qinhuangdao by using FLAC3D software. Based on the engineering example, the different grouting position, spacing and radius of pile side are simulated and analyzed. At the same time, the effects of pile end grouting, pile side grouting and pile end combined grouting on the mechanical performance of cast-in-place pile are compared. Finally, a series of laws are summarized, which can be used to guide practice. The results show that post-grouting can effectively improve the physical properties of pile-soil interface and soil around the pile, squeeze the soil around the pile, and increase the bearing capacity of single pile. The lower the grouting position and the larger the grouting radius, the more effective the bearing capacity of pile can be improved. The effect of grouting spacing on the mechanical behavior of grouting pile is not obvious. The effect of pile end grouting combined with grouting on improving the bearing capacity of pile body is better than that of pile end grouting pile and pile side grouting pile, and the effect of pile end grouting is better than that of pile side grouting.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU753.3

【相似文献】